feat(core): sync io ops in core (#18603)

This commit adds op_read_sync and op_write_sync to core. These ops are
similar to op_read and op_write, but they are synchronous. Just like the
async ops, they operate on generic `deno_core::Resource` objects. These
now have new `read_byob_sync` and `write_sync` methods, with default
implementations throwing "NotSupported" errors, just like the async
counterparts.

There are no `write_all` or `read` equivalents, because the
optimizations they unlock are not useful in synchronous contexts.

core/01_core.js

@@ -412,6 +412,8 @@
     readAll: opAsync.bind(null, "op_read_all"),
     write: opAsync.bind(null, "op_write"),
     writeAll: opAsync.bind(null, "op_write_all"),
+    readSync: (rid, buffer) => ops.op_read_sync(rid, buffer),
+    writeSync: (rid, buffer) => ops.op_write_sync(rid, buffer),
     shutdown: opAsync.bind(null, "op_shutdown"),
     print: (msg, isErr) => ops.op_print(msg, isErr),
     setMacrotaskCallback: (fn) => ops.op_set_macrotask_callback(fn),

core/lib.deno_core.d.ts

@@ -60,6 +60,16 @@ declare namespace Deno {
      */
     function writeAll(rid: number, buf: Uint8Array): Promise<void>;
 
+    /**
+     * Synchronously read from a (stream) resource that implements readSync().
+     */
+    function readSync(rid: number, buf: Uint8Array): number;
+
+    /**
+     * Synchronously write to a (stream) resource that implements writeSync().
+     */
+    function writeSync(rid: number, buf: Uint8Array): number;
+
     /**
      * Print a message to stdout or stderr
      */

core/ops_builtin.rs

@@ -33,6 +33,8 @@ crate::extension!(
     op_read,
     op_read_all,
     op_write,
+    op_read_sync,
+    op_write_sync,
     op_write_all,
     op_shutdown,
     op_metrics,
@@ -279,6 +281,27 @@ async fn op_write(
   Ok(resp.nwritten() as u32)
 }
 
+#[op(fast)]
+fn op_read_sync(
+  state: &mut OpState,
+  rid: ResourceId,
+  data: &mut [u8],
+) -> Result<u32, Error> {
+  let resource = state.resource_table.get_any(rid)?;
+  resource.read_byob_sync(data).map(|n| n as u32)
+}
+
+#[op]
+fn op_write_sync(
+  state: &mut OpState,
+  rid: ResourceId,
+  data: &[u8],
+) -> Result<u32, Error> {
+  let resource = state.resource_table.get_any(rid)?;
+  let nwritten = resource.write_sync(data)?;
+  Ok(nwritten as u32)
+}
+
 #[op]
 async fn op_write_all(
   state: Rc<RefCell<OpState>>,

core/resources.rs

@@ -154,6 +154,18 @@ pub trait Resource: Any + 'static {
     })
   }
 
+  /// The same as [`read_byob()`][Resource::read_byob], but synchronous.
+  fn read_byob_sync(&self, data: &mut [u8]) -> Result<usize, Error> {
+    _ = data;
+    Err(not_supported())
+  }
+
+  /// The same as [`write()`][Resource::write], but synchronous.
+  fn write_sync(&self, data: &[u8]) -> Result<usize, Error> {
+    _ = data;
+    Err(not_supported())
+  }
+
   /// The shutdown method can be used to asynchronously close the resource. It
   /// is not automatically called when the resource is dropped or closed.
   ///

ext/io/12_io.js

@@ -93,27 +93,19 @@ function* iterSync(
 }
 
 function readSync(rid, buffer) {
-  if (buffer.length === 0) {
+  if (buffer.length === 0) return 0;
-    return 0;
+  const nread = core.readSync(rid, buffer);
-  }
-
-  const nread = ops.op_read_sync(rid, buffer);
-
   return nread === 0 ? null : nread;
 }
 
 async function read(rid, buffer) {
-  if (buffer.length === 0) {
+  if (buffer.length === 0) return 0;
-    return 0;
-  }
-
   const nread = await core.read(rid, buffer);
-
   return nread === 0 ? null : nread;
 }
 
 function writeSync(rid, data) {
-  return ops.op_write_sync(rid, data);
+  return core.writeSync(rid, data);
 }
 
 function write(rid, data) {

ext/io/lib.rs

@@ -78,7 +78,6 @@ pub static STDERR_HANDLE: Lazy<StdFile> = Lazy::new(|| {
 
 deno_core::extension!(deno_io,
   deps = [ deno_web ],
-  ops = [op_read_sync, op_write_sync],
   esm = [ "12_io.js" ],
   options = {
     stdio: Option<Stdio>,
@@ -454,7 +453,7 @@ impl StdFileResource {
   }
 
   fn with_inner_and_metadata<TResult>(
-    self: Rc<Self>,
+    &self,
     action: impl FnOnce(
       &mut StdFileResourceInner,
       &Arc<Mutex<FileMetadata>>,
@@ -471,10 +470,7 @@ impl StdFileResource {
     }
   }
 
-  async fn with_inner_blocking_task<F, R: Send + 'static>(
+  async fn with_inner_blocking_task<F, R: Send + 'static>(&self, action: F) -> R
-    self: Rc<Self>,
-    action: F,
-  ) -> R
   where
     F: FnOnce(&mut StdFileResourceInner) -> R + Send + 'static,
   {
@@ -540,6 +536,14 @@ impl StdFileResource {
       .await
   }
 
+  fn read_byob_sync(&self, buf: &mut [u8]) -> Result<usize, AnyError> {
+    self.with_inner_and_metadata(|inner, _| inner.read(buf).map_err(Into::into))
+  }
+
+  fn write_sync(&self, data: &[u8]) -> Result<usize, AnyError> {
+    self.with_inner_and_metadata(|inner, _| inner.write_and_maybe_flush(data))
+  }
+
   fn with_resource<F, R>(
     state: &mut OpState,
     rid: ResourceId,
@@ -632,7 +636,7 @@ impl Resource for StdFileResource {
     Box::pin(async move {
       let vec = vec![0; limit];
       let buf = BufMutView::from(vec);
-      let (nread, buf) = self.read_byob(buf).await?;
+      let (nread, buf) = StdFileResource::read_byob(self, buf).await?;
       let mut vec = buf.unwrap_vec();
       if vec.len() != nread {
         vec.truncate(nread);
@@ -645,17 +649,29 @@ impl Resource for StdFileResource {
     self: Rc<Self>,
     buf: deno_core::BufMutView,
   ) -> AsyncResult<(usize, deno_core::BufMutView)> {
-    Box::pin(self.read_byob(buf))
+    Box::pin(StdFileResource::read_byob(self, buf))
   }
 
   fn write(
     self: Rc<Self>,
     view: deno_core::BufView,
   ) -> AsyncResult<deno_core::WriteOutcome> {
-    Box::pin(self.write(view))
+    Box::pin(StdFileResource::write(self, view))
   }
+
   fn write_all(self: Rc<Self>, view: deno_core::BufView) -> AsyncResult<()> {
-    Box::pin(self.write_all(view))
+    Box::pin(StdFileResource::write_all(self, view))
+  }
+
+  fn write_sync(&self, data: &[u8]) -> Result<usize, deno_core::anyhow::Error> {
+    StdFileResource::write_sync(self, data)
+  }
+
+  fn read_byob_sync(
+    &self,
+    data: &mut [u8],
+  ) -> Result<usize, deno_core::anyhow::Error> {
+    StdFileResource::read_byob_sync(self, data)
   }
 
   #[cfg(unix)]
@@ -684,35 +700,3 @@ pub fn op_print(
     })
   })
 }
-
-#[op(fast)]
-fn op_read_sync(
-  state: &mut OpState,
-  rid: u32,
-  buf: &mut [u8],
-) -> Result<u32, AnyError> {
-  StdFileResource::with_resource(state, rid, move |resource| {
-    resource.with_inner_and_metadata(|inner, _| {
-      inner
-        .read(buf)
-        .map(|n: usize| n as u32)
-        .map_err(AnyError::from)
-    })
-  })
-}
-
-#[op(fast)]
-fn op_write_sync(
-  state: &mut OpState,
-  rid: u32,
-  buf: &mut [u8],
-) -> Result<u32, AnyError> {
-  StdFileResource::with_resource(state, rid, move |resource| {
-    resource.with_inner_and_metadata(|inner, _| {
-      inner
-        .write_and_maybe_flush(buf)
-        .map(|nwritten: usize| nwritten as u32)
-        .map_err(AnyError::from)
-    })
-  })
-}